Function Control Key Locks

ABSTRACT

A lock assembly comprises support means of molded plastic having a plurality of integrally formed cylindrical casings, each casing comprising separate upper and lower interfitting wall sections enclosing key-controlled lock barrel means rotatable from a locked outer inoperative position to an unlocked impulse closure position and from the latter, when depressed inwardly, rotatable to a locked closure position, switch actuating means being provided within each casing to be depressible by the lock barrel in impulse closure position and retained therein when the lock barrel is in a locked closure position. The invention is particularly suitable for use in a business machine, such as a cash register, having a plurality of function control keys.

United States Patent Foss [ FUNCTION CONTROL KEY LOCKS Feb. 4, 1975 Primary Examiner-Robert L. Wolfe Attorney, Agent, or Firm-Davis, McCaleb & Lucas [57] ABSTRACT A lock assembly comprisessupport means of molded plastic having a plurality of integrally formed cylindrical casings, each casing comprising separate upper and lower interfitting wall sections enclosing keycontrolled lock barrel means rotatable from a locked outer inoperative position to an unlocked impulse closure position and from the latter, when depressed inwardly, rotatable to a locked closure position, switch actuating means being provided within each casing to be depressible by the lock barrel in impulse closure position and retained therein when the lock barrel is in a locked closure position. The invention is particularly suitable for use in a business machine, such as a cash register, having a plurality of function control keys.

9 Claims, 5 Drawing Figures FUNCTION CONTROL KEY LOCKS BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates in general to an improved lock for function control keys, particularly suitable for use in a business machine, such as a cash register.

2. Description of the Prior Art Function control key locking means have been provided to selectively afford various types of operation: unlocked impulse closure or momentary switch operation, locked closure operation, and locked inoperative or open switch operation. See, for example, US. Pat. No. 3,026,385, issued on Mar. 20, 1962 to Davis et al. and entitled PUSH-BUTTON OPERATOR WITH LOCKING MEANS.

However, such prior art devices are of complicated design, and utilize component which are whichare difficult and expensive to manufacture.

SUMMARY OF THE INVENTION The present invention is an improved reliable lock assembly which is much simpler in design and less costly to manufacture than known lockable prior art devices. In general, the present invention contemplates one or more function control key locks comprising support means of molded plastic for simple and inexpensive manufacture and having a plurality of cylindrical casings integrally formed therewith, each casing being made up of separate upper and lower interfitting wall sections and housing a key-controlled lock barrel means rotatable from a locked outer inoperative position to an unlocked impulse closure position, switch actuating means being provided within each casing to be depressible by the lock barrel, when the latter is unlocked, from an upper inoperative position to a lower operative switch contact position, each switch actuating means being lockably maintained in such lower operative position by rotation of its associated barrel to locked closure position. Appreciable cost advantages over prior known separately mounted switch devices having complex individually machined components are realized by the simplification of the components employed in the present invention, and particularly as a result of the integral formation of plural cylindrical casing parts with common support means of molded plastic.

An important Object of this invention is to provide a lock for function control keys having a two-part cylindrical casing with each part integrally formed with support means of molded plastic for simple and inexpensive manufacturing.

Numerous other objects and advantages of the invention will be apparent from the following description, which, when taken in conjunction with the accompanying drawings, discloses a preferred embodiment thereof.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of the preferred embodiment of the function control key lock of the present invention, showing two units thereof in different positions;

FIG. 2 is an exploded perspective view showing the component parts of one of the lock units illustrated in FIG. 1;

FIG. 3 is a side elevational view of one of the units in locked inoperative position with parts broken away and parts in vertical section;

FIG. 4 is a horizontal section through the upper end of the cylindrical casing of one of the units taken substantially on the line 44 of FIG. 3; and

FIG. 5 is a horizontal section of one Ofthe units taken substantially on the line 5-5 of FIG. 3.

DESCRIPTION OF THE PREFERRED I EMBODIMENT Turning now to the preferred embodiment of the present invention, reference is initially made to FIGS. 1-3. As shown therein, reference [numeral 10 generally indicates a lockable assembly comprising plural switch units 11, two of which are illustrated in FIG. 1. Each switch unit 11 comprises a preferably molded plastic hollow cylindrical casing section 12 formed integrally with an upper horizontal support plate 13 or other suitable outer support means, the upper or outer end of the casing section 12 terminating in an upstanding flange 14 surrounding a circular opening 16 for receiving a key controlled lock barrel means 17. Also integrally formed with the upper support plate 13 are a plurality of vertical support means comprising vertically depending studs 18 suitably apertured at their lower ends for threadedly receiving an associated plurality of screws 19 for securing a lower horizontal support plate 21 or other suitable inner support means thereto, the lower support plate having screw holes 22 and a central aperture 23 (FIG. 2). Each cylindrical casing section 12 comprises a lower wall portion 24 formed integrally therewith and an upstanding lower wall section 26 is formed integrally with the lower support plate 21 to cooperate with each casing section 12,24 to form a hollow cylindrical casing when the support means 13 and 21 are secured together by studs 18 and screws 19. Each such cylindrical casing has an aperture or recess 27 formed by the partial spatial separation between its wall portion 24 and its lower section 26, and a shelf 28 integrally formed, preferably with the lower casing section, to extend laterally into the aperture 27. As shown in FIGS. 1 and 3, the shelf 28 separates upper and lower slots 29 and 31 in the aperture 27, the upper slot being circumferentially longer than the lower slot 31, as will be more fully described in detail later.

Each key-controlled lock barrel means 17 comprises a known lock barrel or plug rotatable within its cylindrical casing between locked and unlocked positions. Each lock barrel 17 has a key slot 32 in its upper surface adapted to receive an associated key 33, and includes a plurality of outwardly extending lock tumblers 34 (FIG. 2) arranged in a known fashion whereby insertion of an associated key into the key slot causes retraction of the locked tumblers into alignment with the outer surface of the barrel. With additional reference to FIG. 4, which is a horizontal section through the upper end of a cylindrical casing taken substantially on the line of 44 of FIG. 3, the upstanding flange 14 of each casing includes an inner ledge 36 having opposite longitudinal recesses 37 for engageably receiving the outwardly extending lock tumblers of a lock barrel 17 when its key 33 is removed from its key slot 32, insertion of the key enabling rotational movement of the lock barrel within the opening 16.

Each switch unit 11 includes a locking plate means 38 (FIGS. 2, 3 and 5) comprising a plate secured to the bottom of its associated lock barrel 17. A screw 39 fits a hole 41 in each locking plate (FIG. 2) and is threadedly received in a recess 42 in a stud depending from its associated lock barrel, and an alignment stud 43 on this lock barrel engages a hole 44 in the locking plate. Each locking plate 38 has a protruding arm or integral lateral extension 46 outwardly extending into the aperture or recess 27 of its associated cylindrical casing.

Each switch unit 11 further comprises switch actuating plunger means 47 (FIGS. 2 and 3) having a stem 48 and an integral flange 49 engageably disposed beneath its associated locking plate 38. Each plunger 47 in cludes a contact button 51 operable to closingly engage a known pressure-sensitive diaphragn switch 52 (FIG. 3) or other suitable switching means, as described in co-pending application Ser. No. 289,449 for US. Letters Patent, filed Sept 15, 1972, the disclosure of this co-pending application being specifically incorporated herein by reference.

Each plunger 47 is hollowed to provide a bore 53 and apertured to provide opposed ledges 54. Slidable upwardly into each plunger stem 48 is the contact button 51 which has upstanding and opposed cantilever fingers 56 with outwardly extending lugs 57 that spring automatically outwardly into the apertures provided in the wall of each stem. A coiled spring 58 is mounted in each stem 48 with its upper end engaging the latter and its lower end engaging the contact button 51. The function of this spring 58 is to normally maintain the contact button 51 in its extended position (illustrated in the drawings) with the lugs 57 thereby held in the engagement with the ledges 54. Upon depression each stem 47 from its position illustrated in FIG. 3, the contact button 51 associated therewith will be carried downardly through the agency of the spring 58 to close the associated switch 52. After the button 51 first physically contacts the switch 52 during depression of the stem 47, further downward movement of the stem will be relative to the contact button, and the latter will be held in operative position by the spring 58. This arrangement provides the application of a uniform depression force by the contact button 51 on its associated switch 52 and the maximum force that may be applied to the switch is that supplied by spring 58.

A compression spring 59 is provided within each cylindrical casing for biasing an associated plunger 47, locking plate 38 and lock barrel l7 upwardly. Each aperture 27 (FIG. 1) of each cylindrical casing is vertically defined by a horizontal edge 61 (FIGS. 1 and 2) of the lower wall section 26, and a horizontal edge 62 ofthe upper wall portion 24. Each spring 59 is normally operable to bias its associated plunger 47, locking plate 38 and lock barrel 17 upwardly, limited by the engagement of the upper surface of arm 46 with the horizontal edge 62. As noted earlier, each lock barrel 17 is rotatable within the cylindrical casing, upon insertion of a key 33, from a locked inoperative position to an unlocked impulse closure position. The inoperative locked position of each lock barrel 17 corresponds to a position of the arm 46 of its associated locking plate 38 at the left-hand side ofthe aperture 27 and disposed in the upper slot 29 as shown in the right-hand lock in FIGS. 1 and 3. The unlocked impulse closure position of the lock barrel 17 corresponds to a location of the arm 46 at the right-hand side of the aperture 27 unobstructed by, and out of engagement with, the shelf 28, as shown in the left-hand lock in FIG. 1. Each plunger 47 is movable axially within its cylindrical casing 12 in opposition to the biasing force of the spring 59 in response to manual depression of its associated lock barrel 17, when the latter is in its unlocked position, from an upper or outer inoperative position, in which its contact button 51 does not engage a diaphragm switch 52, to a lower or inner switchoperated position, in which the associated switch is closingly engaged by the contact button, in accordance with unobstructed axial movement of its associated arm 46 at the right-hand side of its aperture 27. Each spring 59 normally urges the upper surface of the arm 46 into engagement with a horizontal edge 62 (FIGS. 1 and 2) in the upper inoperative switch position, each plunger being depressible axially to the lower switch-operated position when its lock barrel is unlocked until the lower surface of the arm 46 engages the horizontal edge 61 of its lower wall section 26. In such lower position, rotation of the lock barrel 17 to its locked closure position is permitted by the lower slot 31 receiving the arm 46 and the latter serves to maintain the barrel and the plunger therein.

FIG. 3 illustrates the plunger 47 of a switch unit 1] locked in its upper inoperative position; the arm 46 of the locking 'plate 38 being engaged upwardly of the shelf 28 in the upper slot 29 to render the contact button spatially separated above the diaphragm switch 52. It will be seen that each switch actuating plunger 47 is depressible into its lower switch-operated position only when its associated lock barrel 17 is unlocked and rotated to the impulse closure position shown at the lefthand side of FIG. 1, and the plunger 47 is lockably maintained in either its upper inoperative, or lower switch-operated positions, when its barrel is locked.

As noted earlier, the upper slot 29 of each cylindrical casing is circumferentially longer than the lower slot 31. The opposing recesses 37 of the inner ledge 36 of the upstanding flange 14 of each casing (see FIG. 4), which accommodate the tumblers 34 of a lock barrel 17, are arranged within the inner ledge whereby the position ofthe arm 46 of the locking plate 38 in the upper slot 29 in the extreme left-hand side of the aperture 27 (as illustrated in the right-hand lock of FIG. 1 and in FIG. 3) corresponds to full outward extension of the tumblers 34 into the recesses 37 to enable key insertion and removal. When a lock barrel 17 is locked into the lower closure position corresponding to the location of the arm 46 downwardly of the shelf 28 in the lower slot 31, the tumblers 34 of the lock barrel 17 are not disposed opposite the recesses 37 for outward extension into the latter, thereby preventing key removal from the lock barrel. This arrangement prevents inadvertent removal ofa key 33 from a lock barrel 17 while its associated switch 52 is in a closed position.

With reference to FIG. 5, the wall portion 24 of each cylindrical casing has two spatially separated longitudinal recesses 63 and 64 for engageably receiving a protrusion 66 of the locking plate 38 when its lock barrel 17 is rotated into its locked and unlocked positions, respectively. Each locking plate 38 has a spring means preferably comprising an arcuate peripheral groove 67 disposed opposite the protrusion 66 to urge the latter into one ofthe recesses 63, 64 to effect snap-fit engagement.

It is thought that the invention and many of its attendant advantages will be understood from the foregoing description, and it will be apparent that various changes may be made in the form, construction and arrangement 0f the parts without departing from the spirit and scope of the invention or sacrificing all of its material advantages, the form described being merely a preferred embodiment thereof.

1 claim:

1. Function control key locks, comprising outer support means having a plurality of hollow cylindrical upper casing sections formed integrally therewith, separate inner support means having a plurality of upstanding lower casing sections formed integrally therewith, means for securing said inner and outer support means together to interengage each said upper section with an associated said lower section to present a hollow cylindrical casing, adjacent portions of said associated sections being formed to define a recess in each said casing when said support means are secured together, a key-controlled lock barrel mounted in each said upper casing section for rotation between locked and unlocked positions, a locking plate secured to each said barrel and cooperating with the associated said recess to limit rotational and longitudinal movements of said barrel relative to its associated said casing, and an upwardly spring-urged switchactuating plunger means mounted in each said casing with a lower end extending downwardly through said inner support means, whereby inward longitudinal movement of said barrel when in unlocked position will depress said switchactuating plunger means.

2. Function control key locks according to claim 1, wherein said support means and said casing sections are made of a molded plastic material.

3. Function control key locks according to claim 1, wherein said means for securing said inner and outer support means together comprises a plurality of vertically extending studs formed integrally with one of said support means.

4. Function control key locks according to claim 1, wherein one of said adjacent portions of each associated said casing section is formed to define a shelf extending horizontally into the associated said recess to cooperate with the associated said locking plate to prevent longitudinal movement of the associated said barrel when the same is in locked position.

5. Function control key locks according to claim 4, wherein each said locking plate has an integral lateral extension, and each said shelf divides a portion of the associated said recess into upper and lower slots to accommodate and retain said extension of the associated said locking plate in outer and inner locked position,

respectively.

6. Function control key locks according to claim 5, wherein each said upper slot is longer than each said lower slot to permit rotation of the associated said barrel to a locked inoperative position in which a key operably associated with said barrel may be inserted thereinto or withdrawn therefrom.

7. Function control locks according to claim 1. wherein each said casing has two spatially separated longitudinal recesses each associated with one of said locked and unlocked positions, and each said locking plate comprises integral spring means and a protrusion urged thereby to effect snap-fit engagement of the latter into said recesses of its associated said casing.

8. Function control key locks according to claim 1. wherein each said locking plate cooperates with its associated said casing to positively limit inward longitudinal movement of the associated said barrel, and each said switch-actuated plunger means includes a hollow upper plunger, a switch contact button extending downwardly therefrom for limited downward movement relative thereto, and a spring interposed therebetween to urge said button into extended position, whereby a switch contact disposed below said button can have applied thereto as a maximum force in response to inward movement of the associated said barrel only the force supplied by the associated said spring.

9. A function control key lock, comprising outer support means having a cylindrical upper casing section formed integrally therewith, an inner support means having an upstanding lower casing section formed integrally therewith, means for securing said inner and outer support means together to interengage said upper and lower sections to present a cylindrical casing, adjacent portions of said sections being formed to provide a recess in said casing when said support means are secured together, a key-controlled lock barrel mounted in said upper casing section for rotation between locked and unlocked positions, a locking plate secured to said barrel and cooperating with said recess to limit rotational and longitudinal movements of said barrel relative to said casing, and an upwardly spring-urged switch-actuating plunger means mounted in said casing with a lower end extending downwardly through said inner support means, whereby inward longitudinal movement of said barrel when in unlocked position will depress said switch-actuating plunger means.

=i l= i 

1. Function control key locks, comprising outer support means having a plurality of hollow cylindrical upper casing sections formed integrally therewith, separate inner support means having a plurality of upstanding lower casing sections formed integrally therewith, means for securing said inner and outer support means together to interengage each said upper section with an associated said lower section to present a hollow cylindrical casing, adjacent portions of said associated sections being formed to define a recess in each said casing when said support means are secured together, a key-controlled lock barrel mounted in each said upper casing section for rotation between locked and unlocked positions, a locking plate secured to each said barrel and cooperating with the associated said recess to limit rotational and longitudinal moVements of said barrel relative to its associated said casing, and an upwardly spring-urged switchactuating plunger means mounted in each said casing with a lower end extending downwardly through said inner support means, whereby inward longitudinal movement of said barrel when in unlocked position will depress said switch-actuating plunger means.
 2. Function control key locks according to claim 1, wherein said support means and said casing sections are made of a molded plastic material.
 3. Function control key locks according to claim 1, wherein said means for securing said inner and outer support means together comprises a plurality of vertically extending studs formed integrally with one of said support means.
 4. Function control key locks according to claim 1, wherein one of said adjacent portions of each associated said casing section is formed to define a shelf extending horizontally into the associated said recess to cooperate with the associated said locking plate to prevent longitudinal movement of the associated said barrel when the same is in locked position.
 5. Function control key locks according to claim 4, wherein each said locking plate has an integral lateral extension, and each said shelf divides a portion of the associated said recess into upper and lower slots to accommodate and retain said extension of the associated said locking plate in outer and inner locked position, respectively.
 6. Function control key locks according to claim 5, wherein each said upper slot is longer than each said lower slot to permit rotation of the associated said barrel to a locked inoperative position in which a key operably associated with said barrel may be inserted thereinto or withdrawn therefrom.
 7. Function control locks according to claim 1, wherein each said casing has two spatially separated longitudinal recesses each associated with one of said locked and unlocked positions, and each said locking plate comprises integral spring means and a protrusion urged thereby to effect snap-fit engagement of the latter into said recesses of its associated said casing.
 8. Function control key locks according to claim 1, wherein each said locking plate cooperates with its associated said casing to positively limit inward longitudinal movement of the associated said barrel, and each said switch-actuated plunger means includes a hollow upper plunger, a switch contact button extending downwardly therefrom for limited downward movement relative thereto, and a spring interposed therebetween to urge said button into extended position, whereby a switch contact disposed below said button can have applied thereto as a maximum force in response to inward movement of the associated said barrel only the force supplied by the associated said spring.
 9. A function control key lock, comprising outer support means having a cylindrical upper casing section formed integrally therewith, an inner support means having an upstanding lower casing section formed integrally therewith, means for securing said inner and outer support means together to interengage said upper and lower sections to present a cylindrical casing, adjacent portions of said sections being formed to provide a recess in said casing when said support means are secured together, a key-controlled lock barrel mounted in said upper casing section for rotation between locked and unlocked positions, a locking plate secured to said barrel and cooperating with said recess to limit rotational and longitudinal movements of said barrel relative to said casing, and an upwardly spring-urged switch-actuating plunger means mounted in said casing with a lower end extending downwardly through said inner support means, whereby inward longitudinal movement of said barrel when in unlocked position will depress said switch-actuating plunger means. 